Method and system for providing scene data of virtual world

ABSTRACT

Methods and systems for providing scene data of a virtual world. One method includes the following steps: receiving a request for downloading the scene data from a content requesting party, where the request includes (i) information on an object group in the scene data and (ii) Level of Detail (LoD) information on an object in the object group, packing LoD content of the object in the object group based on the information on the object group and the LoD information on the object, and transmitting the packed LoD content corresponding to the object group to the content requesting party.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 from ChinesePatent Application No. 201010181999.6, filed May 21, 2010, the entirecontents of which are incorporated herein by reference.

BACKGROUND ART

1. Field of the Invention

The present invention generally relates to a field of informationprocessing technology, and in particular, to a method and system forproviding scene data of a virtual world.

2. Related Art

In practical application, downloading methods for scene data havedefects including slow data download, non-continual display of sceneobjects, and other defects that produce a poor user experience.Therefore, there is now a need to overcome the aforementioned one ormore defects so that the user has a better use experience.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a method for providingscene data of a virtual world. The method includes the steps of:receiving a request for downloading the scene data from a contentrequesting party, where the request includes (i) information on anobject group in the scene data and (ii) Level of Detail (LoD)information on an object in the object group, packing LoD content of theobject in the object group based on the information on the object groupin the scene data and the LoD information on the object, andtransmitting the packed LoD content corresponding to the object group tothe content requesting party.

Another aspect of the invention is another method for providing scenedata of a virtual world. The method includes the steps of: transmittinga request for downloading the scene data to a server, where the requestincludes information on an object group in the scene data and Level ofDetail (LoD) information on an object in the object group, andreceiving, from the server, packed LoD content corresponding to theobject group, where the packed LoD content corresponding to the objectgroup is obtained by packing the LoD content of the object in the objectgroup, based on the information on the object group in the scene dataand the LoD information on the object.

Yet another aspect of the present invention is a system for providingscene data of a virtual world. The system includes: downloading requestreceiving means configured to receive a request for downloading thescene data from a content requesting party, where the request includes(i) information on an object group in the scene data and (ii) Level ofDetail (LoD) information on an object in the object group, packing meansconfigured to pack LoD content of the object in the object group basedon the information on the object group in the scene data and the LoDinformation on the object, and transmitting means configured to transmitthe packed LoD content corresponding to the object group to the contentrequesting party.

Yet another aspect of the present invention is another system forproviding scene data of a virtual world. The system includes: a resourcemanagement module configured to: (a) determine (i) information on anobject group in the scene data and (ii) Level of Detail (LoD)information on an object in the object group, and (b) transmit a requestfor downloading scene data to a server, where the request includes theinformation on the object group in the scene data and the LoDinformation on the object in the object group, a downloading managementmodule configured to receive packed LoD content corresponding to theobject group, where the packed LoD content corresponding to the objectgroup is obtained by packing the LoD content of the object in the objectgroup based on the information on the object group in the scene data andthe LoD information on the object, where the packing is performed by theserver.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the following accompanying drawings for describing,in detail, the features and advantages of embodiments of the presentinvention. If possible, same or like reference numerals are used todenote same or like parts throughout the drawings and description.

FIG. 1 illustrates a layered downloading process of a scene object of avirtual world according to an embodiment of the invention.

FIG. 2 illustrates a process of constructing, in layers, an objectaccording to an embodiment of the invention.

FIG. 3 illustrates an embodiment for providing scene data of a virtualworld according to the invention.

FIG. 4 illustrates an area mesh division of a virtual world, and an areainterested by a user.

FIG. 5 illustrates an embodiment for providing scene data of a virtualworld according to the invention.

FIGS. 6 and 7 illustrate a preferred packing method according to theinvention.

FIG. 8 illustrates an embodiment for providing scene data of a virtualworld according to the invention.

FIG. 9 illustrates an embodiment for providing scene data of a virtualworld according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a virtual world domain related to animation, a 3D game (e.g. theWarcraft game), the network virtual life (e.g. the Second Life), thevirtual museum (e.g. the Forbidden City: beyond space and time by IBM),the network virtual shop, and so on, a user needs to download a largeamount of data. Two types of data have to be downloaded among them: onetype of data relates to an update message, i.e. which type of data needsto be frequently updated, but this data amount is small, generally lessthan 100 bits, and presents a small load for the client; another type ofdata is data for constructing scenes, such as an object mesh, an objecttexture, a terrain, and so on. This type of data is much larger becausethe data amount of a general scene is up to tens of megabytes. Forexample, the scene of the Metaverse is 60-80 megabytes, the scene of theWorld of Warcraft is up to 6.6G bytes, and each scene in the Second Lifeis 10-30 megabytes. For this type of data, although most of the data canbe downloaded at only one time upon installation, if this data relatesto a dynamic object, such as a three dimensional object, this data muststill be downloaded dynamically.

Table 1 contains some of the main methods for downloading this type ofdata in a virtual world.

TABLE 1 Data downloading methods Method Advantage DisadvantageApplicable Case HTTP Easy user Long time download, Small scene dataoperation broken easily P2P Fast display Long time download Large gameMultiple-channel Dynamic data are Multiple channels are not Dynamicvirtual world download downloaded only sufficiently utilized similar tothe Second on one channel Life HTTP download Multiple Over largeoverhead for Small dynamic virtual segmentation segmentation dataTTP/TCP/IP header file world similar to the material are downloadedLively through multiple channels

Since the downloading of virtual scene data is normally a verytime-consuming process, a user needs to wait a long time to observescene information. Specific embodiments of the present applicationoptimize a downloading strategy of the scene data, so the user can seeeffective information on the scene in a short response time, whichimproves the user experience. Also, the specific embodiments of thepresent application employ a packed downloading method for incorporatingsmall package data into large package data, such that a huge amount ofredundant header information is reduced to thereby effectively reduce anamount of data transmitted over a network, which improves networktransmission efficiency.

Detailed description with reference to the exemplary embodiments isillustrated in the drawings, where the same elements are denoted by thesame reference numerals. It should be understood that the presentinvention is not limited to the exemplary embodiments disclosed herein.It should be also understood that, not every feature of the method anddevice is necessary for implementing the present invention protected bythe claims. Further, in the whole disclosure, when displaying ordescribing a process or a method, the steps of the method can beperformed in any order or simultaneously, unless it is clear from thecontext that one step depends on another step performed earlier. Inaddition, there can be significant time intervals between steps.

FIG. 1 illustrates a specific downloading practice for a scene object ofa virtual world of the present invention. Where as for the object, inthe case where 10% of the scene data corresponding to the object isdownloaded, the object rendered according to the 10% of the scene datais already clear enough, and a user can already have a betterexperience. Thus, the present application provides every Level of Detail(LoD) content of each object based on a gradual partition, enabling theuser to see the continuous object with better details without waitingover a long time.

Currently, in the industry, normally a form of triangle mesh is adoptedto represent a scene data model of an object. The data in a fileincludes three dimensional coordinates of a point, texture coordinates(a map between a three dimensional point and a two dimensional point ona texture image), and index values of three points of a triangular mesh.However, none of the current model files in the industry provides amethod for Level of Detail (LoD).

There are many studies on a representation method for Level of Detail inthe academy, and a method for gradual transmission can be implemented.For example, the doctoral thesis of Lousbery et al., “MultiresolutionAnalysis for Surfaces of Arbitrary Topological Type,” Doctoral Thesis,Dept. of Computer Science and Engineering, U. of Washington, 1994, anarticle Khodakovsky et al., “Progressive Geometry Compression”,published in the SIGGRAPH 2000 conference, and so on, all set forth somemethods of gradual transmission, but there is no unified standard.

The present invention provides an applicable scene object data solutionsuitable for implementing a LoD transmission. Given an example of athree dimensional virtual world, the scene object data generallyincludes one model file, a plurality of texture files and 0-1 skeletonfile, where the model file includes three parts of a header, a base meshand layered sub-wavelet coefficients data. An exemplary definition ofthe header of the model file thereof is shown as Table 2.

TABLE 2 Byte Type Number Representation and a detailed meaning Int 4 Canbe represented as Magic (‘WAVL’), as verification symbol Int 4 Can berepresented as L, as a layer number of LoD, where the 0-th layer is thebase mesh, sequent lays are sub-wavelet coefficients of the respectivelevel Int 4 Can be represented as BVNUM, as a vertex number of the basemesh Int 4 Can be represented as BFNUM, as a surface number of the basemesh Int 4 Can be represented as BVNUM, as a total number of the vertexnumberIn accordance with the above definition, the point number of the basemesh (base function) of a model file and a number of the sub-waveletcoefficients are totally S=BVNUM*Σ_(i=0) ^(L)4^(i), where i is anon-negative integer, (where the number of sub-wavelet coefficientscorrespond to the point number of the model under each LoD level). Sincea cyclic subdivision is adopted for the base mesh to increase the level,the point number will increase by four times each time the level isincreased by a subdivision. For details, reference can be made to Zorinet al., “Subdivision for Modeling and Animation”, the SIGGRAPH 2000conference.

The base mesh part can consist of triangle sequences, where the specificrepresentation of each triangle is shown as Table 3.

TABLE 3 Type Byte number Detailed meaning Int [3] 4*3 Three vertices oftriangular mesh

As for the third part of the model file, i.e. a Boolean sequence of thesub-wavelet coefficients, it has a total of S/8 bytes (the Boolean isrepresented only by one bit because, since one byte is 8 bits, theBoolean sequence of the sub-wavelet coefficients only needs S/8 bytes)to indicate whether the corresponding coefficients exit. The vertexcoordinates of the base mesh and the number of the sub-waveletcoefficients equal to the number counting the value of 1 among theBoolean sequence of the sub-wavelet coefficients, and M represents thenumber obtained by counting the value of 1 among the Boolean sequence ofthe sub-wavelet coefficients.

Vector3D[M] represents the point coordinates value of the base mesh andthe sub-wavelet coefficients of the respective level, as shown in Table4 (the sub-wavelet coefficients data are represented by a doubleprecision floating point number). Regarding the specific meaning of thesub-wavelet coefficients in the numeral geometry, reference can be madeto Dennago et al., “Uplifted Loop Subdivision Wavelets,” ComputerGraphics and Applications, 12^(th) Pacific Conference (PacificGraphics), 6-8 October, 2004, page 25.

TABLE 4 Type Byte number Detailed meaning Vector3D[M] M*3*sizeof Pointcoordinates value of the base mesh (double) and the sub-waveletcoefficients of the respective level

A specific model file formed according to the aforementioned data modelis shown as Table 5 below.

TABLE 5 Sub-wavelet Sub-wavelet Sub-wavelet File Base mesh coefficientscoefficients coefficients Header data of level 1 of level 2 of level 3 .. . LoD level 1 LoD level 2 LoD level 3 LoD level 4 . . .

FIG. 2 schematically illustrates a data model of scene object data thatcan be used in embodiments of the present invention, where the datamodel consists of a triangular mesh group (TG). FIG. 2 illustrates meshmodels M⁰, {circumflex over (M)}¹, M¹ of a sphere, which are representedby different Level of Detail (LoD) respectively, and the final spheremesh model (FIG. 2 illustrates a process of subdivision increased LoD ofthe object). It should be noted that the triangular mesh group is onlyan example used for the data model of the scene object data; in fact, apolygonal mesh group such as a quadrangular mesh group can also be usedin the embodiments of the present invention. The aforementioned datamodel is only illustrative, and can not be construed to limit thepresent invention. Those skilled in the art can easily construct otherLoD data models to implement the present invention based on the presentinvention.

The scene object data can further include a texture file. The texturefile is an image file generally adopting an image format of jpeg, gif,png, and so on, where jpeg has characteristics of gradual transmission.Thus, the texture file can also be considered as being the image filewith LoD characteristics. Its file format can refer to:http://www.jpeg.org.

The scene object data can further include a skeleton file. The skeletonfile describes a skeleton animation of the model object, which includestwo parts: a skeleton system of the model object and a moving sequenceof the skeleton. The skeleton animation of the model object is generatedbased on the moving sequence of the skeleton. The skeleton file does nothave the method for gradual transmission, and is downloaded as a whole.It can be considered as the skeleton file only having a content of level0 LoD. As for construction of the object model in the two dimensionalvirtual world, those skilled in the art can certainly perform theconstruct more easily, and this will no longer be repeated herein.

As for the virtual world based on, or at least partially based on, theLoD data model, the present invention proposes a first specificembodiment as shown in FIG. 3. In step 301, a request for downloadingscene data is received from a content requesting party. The requestincludes information on each object group in the scene data and Level ofDetail (LoD) information on each object in the object group. The objectsof the scene data to be downloaded are grouped based on an Area ofInterest (AoI), where user's viewpoint is located as shown in FIG. 4, toform the shown object group.

In the scene model of the virtual world, an area division, as shown inFIG. 4, can be performed (for simplicity, the description is made byusing the two dimensional method). For example, when a scene size is1024*1024 and a size of an equally divided cell area is 128*128, thenthe scene of the whole virtual world is divided into 64 cell areas. Aglobal unique identifier of each cell area is corresponding X, Ycoordinates. For example, the coordinates of an area 41 where the userviewpoint is located is (3, 4). It should be noted that these data areonly illustrative, and cannot be construed to limit the presentinvention.

A radius of the Area of Interest (AoI), including the user viewpoint,can be set as one cell, that is, the areas whose distance to the cellwhere the current viewpoint is located are the Area of Interest 43, andcertainly a plurality of cells can be set as the radius as necessary.Although the scene mesh division in terms of square is provided hereinas an example, various shape of mesh division can be adopted.

The location where each object in the scene of the virtual world islocated, at anytime, can be recorded by a server; for example, thecoordinates of an object O 47 in FIG. 4 in the virtual world are (576,576), so it can be calculated that object O 47 is inside the cell (4, 4)(if it is a three dimensional representation, then a Z directioncoordinate should be added). So it can be determined that the area to bedownloaded is the area where the viewpoint is located and thesurrounding 8 areas.

A content requesting party (e.g., a client, or a client proxy and so on)can prioritize requesting for downloading the object group formed by theobjects included in the area 41, where the viewpoint is located, andthen request a one by one, in layer, download of the object groupsformed by the objects included in the other surrounding 8 cellsaccording to a clockwise/counter clockwise method. Of course, theobjects in the Area of Interest 43 can also be required to be grouped asone object group to be downloaded just once.

The identifier of the object groups can adopt the unique globalidentifier in the area. For example, an embodiment of the invention canemploy area coordinates (x, y) (for three dimensional representation,the Z direction coordinate will be added), and another embodiment of theinvention can also adopt an identification information on the objectgroup by combining the unique identifiers of each object. The methodwhich adopts the cell area radius to determine the AoI area cansignificantly reduce the computation amount of the server, andsignificantly improve the user's experience. Of course, those skilled inthe art can envision various identification methods, prioritydownloading strategies, and different applicable AoI definitions.

In addition, the content requesting party also provides Level of Detail(LoD) information on the object in the object group in the downloadingrequest, that is, which level of the LoD content of the object iscurrently required to download. The area shown by broken lines can beextended in subsequent downloading, if necessary.

More levels of LoD content can be downloaded for the AoI than those forother areas. For example, the 2^(nd) level of LoD content is downloadedfor the AoI, and the 1^(st) level of LoD content is downloaded for thearea beyond the broken line, which is helpful because it guarantees adisplay quality for the user's AoI and it improves the user'sexperience.

In step 303, the LoD content of the object in the object group is packedaccording to the information on the object group in the scene data andthe LoD information on the object. Since the downloading request of thecontent requesting party includes the information about the object groupin the scene data and the LoD information about the object, each objectin the object group and the scene object data corresponding to eachobject can be found through the information about the object group inthe scene data. Additionally, the level of the LoD content of the objectthat is required to be downloaded can be determined by using the LoDinformation on the object. All of the obtained LoD contents are packed.

A preferred embodiment where all the LoD contents are packed will bedescribed below in connection with FIG. 5.

In step 305, the packed LoD contents corresponding to the object groupare transmitted to the content requesting party. By adopting the firstspecific embodiment of the present invention, the user is enabled tofluently see a plurality of objects in the scene of the virtual world,rather than the prior art where there are defects such as long waitingtime and discontinuously presented objects in the viewed scene.

FIG. 5 illustrates a second specific embodiment of the presentinvention, which is a further particular optimization for the abovedescribed step 303. In step 501, a LoD model file corresponding to theobject of the object group is acquired. Since the content server recordsthe objects included in the current area, if the global identifier ofthe area is provided in the downloading request from the contentrequesting party, the LoD model file corresponding to the objects can beretrieved based on the records. If the downloading request directlyprovides the unique identifiers of a plurality of objects to the contentserver, then the LoD model file corresponding to the objects can beretrieved directly based on the unique identifiers of these objects.

In step 503, the LoD content designated by the LoD information on theobject is extracted based on the acquired LoD model file. The LoD modelfile adopts a layered method to record the scene data of the objectaccording to the LoD information on the object, i.e. which layer of theLoD content is required. The data block of LoD content of the layer isextracted from the LoD model file of the scene object data.

In step 505, the extracted LoD content designated by the LoD informationon the object is packed. In the prior art, it is apt to respectivelypack the aforementioned plurality of LoD contents into a plurality ofHTTP packages to be sent to the user, so that there are a lot ofoverheads of headers.

FIGS. 6 and 7 illustrate a preferred packing method for the presentinvention. Unlike the prior art, and as shown in FIG. 6, the presentinvention packs the aforementioned plurality of LoD contents into alarge HTTP package to be sent to the user, so that a lot of overhead ofheaders is saved.

FIG. 7 illustrates a data format of a formed package, where the packeddata is a package data which includes three parts of data: a headerrecording an ID of the package data (a version number, a size (bytenumber) of the whole package data, and counts containing the sceneobjects), middle data recording the object data of each scene (Obj1data, Obj2 data, . . . ), and a CRC checking code. The object data ofeach scene can include three kinds of data: one model data, one or moretexture data, and 0-1 skeleton data. The object data of the scene is thefollowing data in order:

Object ID (Obj ID): a data with a fixed size;

Level of Detail (LoD) information: a data with a fixed size;

Block counts included in the object data: a data with a fixed size;

The following are data blocks in order; each data block includes thefollowing data:

Data block ID: a data with a fixed size;

Data type: model data, texture data or skeleton data, a data with afixed size;

Data size in bytes of the data block: a data with a fixed size;

Actual data of the data block, variable data, and the size is the bytenumber given by the last data end.

The aforementioned package data is only illustrative, and it can not beconstrued as the specific limitation to the present invention.

As a preferred embodiment, a unique package data identifier can begenerated for the above package data, and sent to the content requestingparty. The content requesting party receives the unique identifier ofthe package data, and requests that the package data be downloaded, thecontent server sends to the content requesting party the packed LoDcontent corresponding to the object group according the request. Byemploying this method, the content requesting party can avoid asituation of an idle wait, while waiting for packing after sending thedownloading request. This is helpful because it improves the utilizingefficiency of the content requesting party.

FIG. 8 illustrates a third specific embodiment in connection with asystem for providing scene data of a virtual world of the presentinvention. A whole method flow and system of the present invention aredescribed in detail below.

As shown by arrow 1, a resource management module of a client receives adownloading request formed by a list of a scene object group, which issent by a Human Computer Interaction and Graphical User Interface modulebased on a user's viewpoint.

As shown by arrow 2, the resource management module 809 of the contentrequesting party 801 checks whether a local buffer 807 has resourcefiles of these scene objects, then scene objects having resource fileslocally will be deleted from the list of a scene group in thedownloading request. In a step 3, the content requesting party 801initiates computation of the downloading strategy. There are manymethods for the downloading strategy; for example, generating a list ofan object group including a scene object according to the aforementionedconcept of the Area of Interest (AoI) and the Level of Detail (LoD),then sorting according to a distance between a cell of Area of Interest(AoI) and the viewpoint. A cell with a close distance can be placed at afront of the list, otherwise at a back of the list, or simplydownloading the surrounding cells of the Area of Interest (AoI) inaccordance with the clockwise direction, and so on. Those skilled in theart can choose any suitable downloading strategy based on the presentapplication.

As shown by arrow 4, the content requesting party 801 sends to a virtualworld server 803 the downloading request regarding the object group,including the scene object required to be downloaded in priority in thelist. The downloading request includes identification information on theobject group and Level of Detail (LoD) information on the object in theobject group.

As shown by arrow 5, the virtual world server 803 receives thedownloading request, and a content service module 811 of the virtualworld server 803 finds from a resource database 813 corresponding filedata for packing. The method for packing can be based on the variousimplementing methods illustrated above. As shown by arrow 6, the virtualworld server 803 generates a unique identifier for the packed data andsends it to the content requesting party 801, and meanwhile informs thatthe downloading is available.

Proceeding to a step as shown by arrow 7, the resource management module809 of the content requesting party 801 receives the unique identifierof the packed data, and forwards to a downloading management module 815to start the downloading task.

In the step as shown by arrow 8, the content requesting party 801 startsdownloading the packed data. The downloading process can be multiplethreads to download a plurality of packed data, and can also perform thedownloading by using the methods such as HTTP, FTP, TCP/IP.

In a step, as shown by arrow 9, the content requesting party 801 canparse the downloaded content after part of the contents have beendownloaded without waiting for the whole contents to be completelydownloaded; certainly, it can also perform the parsing after the wholepackage has been completely downloaded. If a low Level of Detailrepresentation data is found in the local buffer 807, current data (suchas the LoD content of the current level) and previous data (such as theLoD content of other level) are combined to generate new data, and theparsed data or the combined data are stored in the local buffer 807.Since the sent packed data use the data structure as shown in FIG. 7,the parsing in the content requesting party 801 can be carried outaccording to the following method:

1) First, reading the header, determining how many objects' scene objectdata are included in the packed LoD content corresponding to the objectgroup;

2) sequentially reading the LoD content of the scene object data of eachobject:

a) reading the scene object ID;

b) reading the Level of Detail (LoD) of the scene object data;

c) reading the data block counts contained in the scene object;

d) sequentially reading the data block data:

-   -   i. reading a data block ID;    -   ii. reading the data block type, if it is model data, it        proceeds to the processing flow of model data; if it is texture        data, it proceeds to the processing flow of texture data; if it        is skeleton data, it proceeds to the processing flow of skeleton        data;    -   iii. reading the data size in bytes of the data block;    -   iv. reading as much data as the bytes designated in the above        step, and then performing the corresponding type of process        according to the type of the data block.

The present invention is not limited to the above parsing method, and ofcourse, those skilled in the art can also conceive other implementingmethod for parsing based on the present invention.

Proceeding to a step as shown by arrow 10, after the new data aregenerated, the resource management module 809 can be informed to updatedata, and then, as shown by arrow 11, a rendering engine 817 performsplotting based on the new data, so as to present the scene object of therelated virtual world to the user.

Another aspect of the present invention also provides a system 900 forproviding scene data of a virtual world. The system 900 includes adownloading request receiving means 901, a packing means 903 and atransmitting means 905, where the downloading request receiving means901 is for receiving a request for downloading scene data from a contentrequesting party, and the request includes information on an objectgroup in the scene data and Level of Detail (LoD) information on anobject in the object group; the packing means 903 is for packing LoDcontents of the object in the object group based on the information onthe object group in the scene data and the LoD information on theobject; and the transmitting means 905 is for transmitting the packedLoD contents corresponding to the object group to the content requestingparty, where the information on the object group includes a globalidentifier of the object group in the virtual world, where the LoDinformation on the object in the object group includes LoD contents ofthe object at which level is required to be downloaded.

Preferably, the scene data of the object includes a LoD model file, thepacking means 903 includes: means for retrieving the LoD model filecorresponding to the object in the object group; means for extractingthe LoD contents designated by the LoD information on the object basedon the retrieved LoD model file; means for packing the extracted LoDcontents corresponding to the object group.

Preferably, the means for packing the extracted LoD contentscorresponding to the object group includes: means for forming theextracted LoD contents into a package data, where the package dataincludes a header and an object data, the header records counts ofobjects included in the object group, and the object data of the objectin the object group includes the LoD contents corresponding to theobject.

Preferably, the scene object data of the object also includes at leastone of a texture file and a skeleton file, where the texture fileincludes the LoD contents.

Preferably, the transmitting means 905 includes: means for transmittinga unique identifier of the package data formed by the packed LoDcontents to the content requesting party; means for, in response to therequest for downloading the package data by the content requesting partyaccording to the received unique identifier of the package data,transmitting the packed LoD contents corresponding to the object groupto the content requesting party.

Preferably, the object group includes objects in a user's Area ofInterest (AoI), the object in the object group includes a threedimensional dynamic object, the system further includes means fordetermining the user's AoI by a way of using a cell area radius of thevirtual world.

In addition, the method and system for providing scene data of thevirtual world according to the present invention can also be implementedby a computer program product, which includes a software code partexecuted to implement a simulation method for the present invention whenthe computer program product is operated in a computer.

The present invention can also be implemented by a computer programrecorded in a computer-readable recording medium, and the computerprogram includes a software code part executed to implement a simulationmethod for the present invention when the computer program product isoperated in a computer. That is, the process according to the simulationmethod for the present invention can be distributed in the form ofinstructions in the computer-readable medium and in various other forms,regardless of the particular type of the signal bearing medium actuallyused to perform the distribution. Examples of the computer-readablemedium include the medium such as an EPROM, a ROM, a magnetic tape, apaper, a floppy disk, a hard disk driver, a RAM and a CD-ROM, and atransmission type media such as a digital and analog communication link.

While the present invention has been shown and described in detail withreference to the preferred embodiments of the present invention, itshould be understood by those skilled in the art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention as defined by the appended claims.

What is claimed is:
 1. A method for providing scene data of a virtualworld, the method comprising: receiving a request for downloading saidscene data from a content requesting party, wherein said requestincludes (i) information on an object group in said scene data and (ii)Level of Detail (LoD) information on an object in said object group,wherein scene data of said object includes a LoD model filecorresponding to said object in said object group; packing LoD contentof said object in said object group based on said information on saidobject group in said scene data and said LoD information on said objectby: acquiring said LoD model file corresponding to said object,extracting said LoD content designated by said LoD information on saidobject using said acquired LoD model file, and packing, into a singleHTTP package to be sent to said content requesting party, said extractedLoD content designated by said LoD information on said object by formingsaid extracted LoD content into a package data, wherein said packagedata includes a header and an object data, wherein said header recordscounts of objects in said object group, and wherein said object datacomprises data of said object in said object group; and transmittingsaid packed LoD content corresponding to said object group to saidcontent requesting party, wherein said transmitting further comprises:transmitting a unique identifier of a package data to said contentrequesting party, wherein said package data is formed by said packed LoDcontent; and responding to a request for downloading said package databy transmitting said packed LoD content corresponding to said objectgroup to said content requesting party, wherein said request is made bysaid content requesting party, and wherein said request is madeaccording to said unique identifier.
 2. The method according to claim 1,wherein said scene data of said object further comprises a texture filethat includes said LoD content.
 3. The method according to claim 1,wherein said object group includes objects in an Area of Interest (AoI)of a user, and wherein said object in said object group includes a threedimensional dynamic object.
 4. The method according to claim 3, whereinsaid AoI of a user is determined by using a cell area radius of saidvirtual world.
 5. The method according to claim 1, wherein said LoDinformation on said object in said object group includes information onLoD content of said object at a level required for download.
 6. Themethod according to claim 1, wherein said information on said objectgroup includes a global identifier of said object group in said virtualworld.
 7. The method according to claim 6, wherein said globalidentifier of said object group in said virtual world is coordinates ofa cell area of said virtual world where said object in said object groupis located.
 8. A non-transitory computer readable storage medium havingexecutable programming instructions stored thereon which, whenimplemented, cause a computer to carry out the steps of the methodaccording to claim
 1. 9. The method according to claim 1, wherein saidheader records an ID of the packaged data, the ID including a versionnumber, and a number of bytes of the packaged data.
 10. The methodaccording to claim 1, wherein said data of said object in said objectgroup includes: an object ID; level of detail information; and a countof data blocks included in the object data; and with a data typeselected from a plurality of data types including model data, texturaldata, and skeleton data.
 11. A method for providing scene data of avirtual world, the method comprising: transmitting a request fordownloading said scene data to a server, wherein said request includes(i) information on an object group in said scene data and (ii) Level ofDetail (LoD) information on an object in said object group; andreceiving, from said server, packed LoD content corresponding to saidobject group, wherein said packed LoD content corresponding to saidobject group is obtained by packing said LoD content of said object insaid object group based on said information on said object group in saidscene data and said LoD information on said object, wherein scene dataof said object includes a LoD model file corresponding to said object insaid object group, and wherein said packing includes: acquiring said LoDmodel file corresponding to said object, extracting said LoD contentdesignated by said LoD information on said object using said acquiredLoD model file, and packing, into a single HTTP package to be sent tosaid content requesting party, said extracted LoD content designated bysaid LoD information on said object by forming said extracted LoDcontent into a package data, wherein said package data includes a headerand an object data, wherein said header records counts of objects insaid object group, and wherein said object data comprises data of saidobject in said object group wherein said receiving, from said server,packed LoD content corresponding to said object group further comprises:requesting said server to download said package data based on a uniqueidentifier, wherein said request is made in response to receiving saidunique identifier of said package data, and wherein said package data isformed by packing said LoD content of said object group in said objectgroup transmitted by said server; and receiving said packed LoD contentcorresponding to said object group transmitted by said server.
 12. Themethod according to claim 11, wherein said downloading request includesan object group list of said scene determined according to a viewpointof a user, and the method further comprises: checking whether a localbuffer has resource files of an object in an object group in said objectgroup list; deleting an object of said scene having a local resourcefrom an object group in said object list; determining a downloadingpriority order for said object group in said list according to apredetermined downloading strategy; and generating said request fordownloading said scene data according to said downloading priorityorder.
 13. The method according to claim 11 further comprising:determining an amount of scene data corresponding to objects in saidobject group that is included in said packed LoD content correspondingto said object group; sequentially reading LoD content of scene data ofeach object in said object group; and performing a scene rendering basedon said sequential reading.
 14. The method according to claim 11 furthercomprising: determining an amount of scene data corresponding to objectsin said object group that is included in said packed LoD contentcorresponding to said object group; sequentially reading LoD content ofscene data of each object in said object group; and performing a scenerendering based on said sequential reading.
 15. A non-transitorycomputer readable storage medium having executable programminginstructions stored thereon which, when implemented, cause a computer tocarry out the steps of the method according to claim
 11. 16. The methodaccording to claim 11, wherein said data of said object in said objectgroup includes: an object ID; level of detail information; and a countof data blocks included in the object data; and with a data typeselected from a plurality of data types including model data, texturaldata, and skeleton data.
 17. A system for providing scene data of avirtual world, the system comprising: memory with computer instructionsstored therein; a processor communicatively coupled to the memory andconfigured to execute the computer instructions to perform: receiving arequest for downloading said scene data from a content requesting party,wherein said request includes (i) information on an object group in saidscene data and (ii) Level of Detail (LoD) information on an object insaid object group; packing LoD content of said object in said objectgroup based on said information on said object group in said scene dataand said LoD information on said object, wherein scene data of saidobject includes a LoD model file corresponding to said object in saidobject group, and wherein said packing includes: retrieving said LoDmodel file corresponding to said object, extracting said LoD contentdesignated by said LoD information on said object based on saidretrieved LoD model file, and packing, into a single HTTP package to besent to said content requesting party, said extracted LoD content byforming said extracted LoD content into a package data, wherein saidpackage data includes a header and an object data, wherein said headerrecords counts of objects included in said object group, and whereinsaid object data of said object in said object group includes said LoDcontent corresponding to said object; and transmitting said packed LoDcontent corresponding to said object group to said content requestingparty, wherein said transmitting further comprise: transmitting a uniqueidentifier of a package data formed by said packed LoD content to saidcontent requesting party; and responding to a request for downloadingsaid package data by transmitting said packed LoD content correspondingto said object group to said content requesting party, wherein saidrequest is made by said content requesting party, and wherein saidrequest is made according to said unique identifier.
 18. The systemaccording to claim 17, wherein scene data of said object also includes atexture file that includes said LoD content.
 19. The system according toclaim 17, wherein said object group includes objects in an Area ofInterest (AoI) of a user, wherein said object in said object groupincludes a three dimensional dynamic object, and wherein said systemfurther comprises determining said AoI of a user by using a cell arearadius of said virtual world.
 20. The system according to claim 17,wherein said data of said object in said object group includes: anobject ID; level of detail information; and a count of data blocksincluded in the object data; and with a data type selected from aplurality of data types including model data, textural data, andskeleton data.
 21. A system for providing scene data of a virtual world,the system comprising: memory with computer instructions stored therein;a processor communicatively coupled to the memory and configured toexecute the computer instructions to perform: (a) determining (i)information on an object group in said scene data and (ii) Level ofDetail (LoD) information on an object in said object group, and (b)transmitting a request for downloading scene data to a server, whereinsaid request includes said information on said object group in saidscene data and said LoD information on said object in said object group;and receiving packed LoD content corresponding to said object group,wherein said packed LoD content corresponding to said object group isobtained by packing said LoD content of said object in said object groupbased on said information on said object group in said scene data andsaid LoD information on said object, wherein said packing includes:acquiring said LoD model file corresponding to said object, extractingsaid LoD content designated by said LoD information on said object usingsaid acquired LoD model file, and packing, into a single HTTP package tobe sent to said content requesting party, said extracted LoD contentdesignated by said LoD information on said object by forming saidextracted LoD content into a package data, wherein said package dataincludes a header and an object data, wherein said header records countsof objects in said object group, and wherein said object data comprisesdata of said object in said object group wherein said packing isperformed by said server; and transmitting said packed LoD contentcorresponding to said object group to said content requesting party,wherein said transmitting further comprises: transmitting a uniqueidentifier of a package data to said content requesting party, whereinsaid package data is formed by said packed LoD content; and respondingto a request for downloading said package data by transmitting saidpacked LoD content corresponding to said object group to said contentrequesting party, wherein said request is made by said contentrequesting party, and wherein said request is made according to saidunique identifier.
 22. The system according to claim 21, wherein saiddata of said object in said object group includes: an object ID; levelof detail information; and a count of data blocks included in the objectdata; and with a data type selected from a plurality of data typesincluding model data, textural data, and skeleton data.